The Cell Imaging Subcore was started in September, 1993. The objective of this subcore is to provide access to, and expert assistance in, the use of a state-of-the-art laser scanning confocal microscope. Advice is available on immunostaining, dynamic fluorescence imaging, and computer-based image processing. The key resource of this subcore is a Zeiss LSM410 confocal microscope equipped with an external Ar-Kr laser. Four Silicon Graphics workstations equipped with image analysis software support the analysis and visualization of the large and complex data sets generated by the confocal microscope. Researchers who use this resource receive assistance with three-dimensional image processing, visualization, and hard copy output. In the presubmission survey of DRTC members, 22% indicated that they anticipated extensive use of this subcore. At least seven DRTC investigators currently use this subcore extensively for diabetes-related studies.